Asteroid Strike on Moon Created Two Grand Canyons in Just 10 Minutes

WASHINGTON—The Grand Canyon in Arizona stands as one of the planet’s extraordinary natural marvels, shaped over millennia by the persistent erosive force of the Colorado River. In contrast, two canyons located near the moon’s south pole match the Grand Canyon in size but were formed through a significantly different mechanism.

Recent studies reveal that these lunar canyons, found in the Schrödinger impact basin on the moon’s far side, were formed in under 10 minutes by debris ejected at high velocity when either an asteroid or comet struck the moon around 3.8 billion years ago.

This colossal impact released an energy equivalent to approximately 130 times the total yield of today’s nuclear weapons inventory, as noted by geologist David Kring from the Lunar and Planetary Institute associated with the Universities Space Research Association in Houston. He is the lead author of the study published on Tuesday in the journal Nature Communications.

The team analyzed the canyons using data from NASA’s Lunar Reconnaissance Orbiter spacecraft, complemented by computer simulations to ascertain the trajectories and speeds of the debris. Their findings showed that the ejected material would have traveled at speeds reaching roughly 2,200 miles per hour.

The first canyon, named Vallis Planck, stretches approximately 174 miles long and is 2.2 miles deep, while the second, Vallis Schrödinger, measures about 168 miles long and 1.7 miles deep.

This event took place during a period of intense bombardment across the inner solar system, caused by space rocks that were believed to have been dislodged due to gravitational shifts among the solar system’s larger planets—Jupiter, Saturn, Uranus, and Neptune—around the same timeframe.

The asteroid that impacted the moon is estimated to have had a diameter of around 15 miles.

According to Kring, “When the asteroid or comet impacted the lunar terrain, it excavated an immense volume of rock that was propelled into space before eventually falling back down. Clusters of rocks from that cloud of debris impacted the surface in a series of smaller events, effectively sculpting the canyons. The surrounding landscape would have been blanketed by the debris.”

The canyons appear as straight scars on the lunar surface, originating from a large, circular impact crater, with minor craters from unrelated impacts also nearby.

This impact represents one of the last major collisions that occurred on the surfaces of the moon and Earth during this bombardment phase in the early solar system. While the moon retains these scars, Earth does not.

This difference is attributed to Earth’s surface being continually renewed through a geological process known as plate tectonics, where massive rock plates move very slowly. At their edges, one plate may dive beneath another, taking surface rock deep within the planet. In contrast, the moon, being less geologically active, lacks this process.

The new insights are particularly relevant for future lunar exploration. The Schrödinger impact basin is located near the target area for NASA’s upcoming Artemis mission, which aims to land astronauts on the moon for the first time since the Apollo missions of the 1970s.

Kring expressed, “Since debris from the Schrödinger impact was thrown away from the moon’s south pole, ancient rocks in the polar area will likely be at or near the surface, making sample collection for Artemis astronauts much easier. Consequently, they will be able to gather samples from the earliest phases of lunar history.”

These rocks could allow researchers to investigate theories regarding the moon’s origin, specifically the notion that it formed from material cast into space from a massive impact with Earth, as well as the idea that the early lunar surface was an ocean of molten material, Kring added.